Johnson played the iconic role of Professor Roy Hinkley, whose scientific schemes to get the castaways rescued were always foiled by Gilligan's bumbling.

He died at his home in Washington, where he lived with his wife, Connie. She and their daughter, Kimberly, were at his side, said agent Mike Eisenstadt. Johnson is also survived by a stepson, Court, and a grandson, he said.

Johnson worked up until his death, signing autographs at public appearances over the holidays, said Eisenstadt. He called his death "unexpected."

He was "just a positive and nice guy," who always treated people with respect, his agent said.

His acting career began in the early 1950s with many jobs as a character actor on television. He played Marshal Gib Scott in two seasons of "Black Saddle," a western that ran in 1959 and 1960.

Johnson acted in dozens of television shows after the four seasons on "Gilligan's Island," but his career seemed stranded on its own island because of the iconic role of Professor Roy Hinkley.

"Gilligan's Island" aired on CBS from September 1964 to September 1967.

The show followed seven castaways as they attempt to escaped from the island where they've been shipwrecked.

"The Professor" was in fact a high school science teacher, not a university professor.